The invention relates to a damper arrangement in a water heater. It is known to use a damper in a water heater flue. Known dampers use a physical obstruction to close the flue during standby. One example of a physical obstruction type damper is disclosed in U.S. Pat. No. 4,953,510.
The invention relates to a damper arrangement that uses an airflow apparatus to substantially reduce standby heat loss due to natural convection cycles in a water heater flue.
The invention includes a water heater having a water tank adapted to contain water, a combustion chamber beneath the water tank, a burner within the combustion chamber and operable to create products of combustion, and a flue extending substantially vertically through the water tank. The flue communicates with the combustion chamber to conduct the products of combustion from the combustion chamber and to transfer heat to water stored within the water tank. The water heater also includes an airflow apparatus capable of creating airflow in the absence of any opposition to the airflow. The airflow apparatus communicates with the flue and resists standby convection flow of flue gases out of the flue when the burner is not operating.
In one construction, the airflow apparatus is automatically adjustable to vary the magnitude of the airflow to more effectively counteract the standby convection flow of flue gases out of the water heater when the burner is not operating.
In another construction, the airflow apparatus is operable to create a downward airflow in communication with the flue when the burner is not operating to counteract standby convection flow of flue gases and is also operable to create an upward airflow in communication with the flue when the burner is operating to assist the exhaust of the products of combustion from the flue.
In a further aspect, the airflow apparatus creates airflow to counteract the standby convection flow of flue gases when the burner is not operating and an additional airflow apparatus mixes air with the products of combustion from the combustion chamber prior to entering a catalytic converter to improve the effectiveness of the catalytic converter when the burner is operating, and preferably at startup of the water heater.
In yet another construction of the invention, the airflow apparatus is an ionic airflow device connected to an over current device that disconnects power to the ionic airflow device in the event of an arcover.
In a further construction, the airflow apparatus is an ionic airflow device electrically connected to the same high-voltage power supply that powers an ignitor of a direct ignition system of the water heater.
In another embodiment of the invention, an airflow apparatus creates an airflow in communication with the flue when the burner is operating to create a backpressure in the flue that increases the residence time of the products of combustion within the flue.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.